As of 2015, casinos must issue a form W-2G when bingo or slot machine winnings are $1,200 or more, $1,500 or more when playing keno or $5,000 or more in winnings from a poker tournament, as stated by Bankrate. Winnings at the horse track or other gambling activities that are more than 300 times the initial bet or greater than $600 are reported.
Casinos withhold 25 percent of reported winnings to help satisfy the winner's tax obligation. Even if the casino or gambling establishment does not issue a W-2G, tax payers are required to report gambling or prize winnings. Tax payers that itemize can deduct their gambling losses to help offset the winnings, but only up to the value of the winnings, as stated by the IRS.